could you send me the log generated by squid and videocache since request begin, also as i understand that the videocache already download the file but you can't hit it when you try to browse the same file again, also i want to know if that happen with all youtube videos or some of them ?

I suggest that admin shld involve/agree in any changes that is needed for videocache . This can be in terms of patches instead we are making trial and error and eventually we will have a very different version form the original conf.